What makes Snap Casts (Interesting)

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What makes Snap Casts (Interesting)

Post Number:#11  Postby VGB » Mon Apr 16, 2018 8:47 am

Hi Dirk

This point is also interesting, it appears to show that changes to v-fly and v-loop do not follow each other immediately as described by the tension model. I think I see the delay also when I make the cast, do you think there are any other possible causes than a testing issue?

And whereas the rod tip’s acceleration reversal point coincides with the threshold of an acceleration plateau in markers 3 and 4, it precedes the threshold point of the loop’s acceleration plateau by one step...

This time step difference may be due to coarse steps used and requires calling for the magnification glass some time in future.


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What makes Snap Casts (Interesting)

Post Number:#12  Postby Dirk le Roux » Mon Apr 16, 2018 1:07 pm

VGB wrote:
So rod tip acceleration from here on is visibly impeded (by what?)


I think that the rod tip acceleration is impeded by the combined inertia of the fly leg and rod tip. I think it’s another occurrence of the rod tip going backwards when we first accelerate the rod.

Hi Vince

I checked again and during the time after the instant shown, the rod is progressively less bent. It may be an occurrence of Graeme having begun the stop, so impeded by less input.

All the best, Dirk
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What makes Snap Casts (Interesting)

Post Number:#13  Postby Dirk le Roux » Mon Apr 16, 2018 1:22 pm

Graeme H wrote:I'm interested to see slightly positive rod tip acceleration at the highlighted frame in the last image posted above. The rod is still bent, indicating there is still some downward force, even if it's not full power. The graph indicates the tip is about to stop accelerating in the opposite direction to the force I'm applying, so its downward velocity is constant at that exact point. I guess it's a function of the image frame chosen at that very point, because the next point on the plot has positive acceleration (rod tip slowing.)

Hi Graeme

There may be some downward force still applied by the rod tip at that point, but as you can see from the plot, the tip's downward acceleration at that instant has already ceased and is now downward deceleration/upward acceleration. The downward force displayed by the bend there is likely smaller than the upward force at the loop at that time.

Regards, Dirk
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